The amp is effectively a discreet 6 channel amplifier. At its simplest, you could just parallel your source across all 6 inputs, or you could be swish and put a small mixer/router in so you could route different sources to different speakers, you could have the empeg on in one room and the radio in another.

You could either buy adaptor cables or simply make them up by chopping RCA cables in half and screwing the bare ends into the phoenix connectors.